The Captain Corrosion smart radiation shielding material provides protection for electronic devices against ionizing radiation in conditions, where complete shielding is not possible due to weight and dimension limitations (e.g. with a thick layer of lead). This allows to enhance the lifetime of semiconductor-based electronics in high radiation environments.
Applications
Satellites – in space devices are exposed to high velocity particles and also to high energy electromagnetic radiation, where the latter one is also created when the particles interact with the exterior of the spacecraft. Shielding against radiation in space is difficult however, as complete protection is not possible (weight and thickness limitations) and single-layer shielding materials create dangerous secondary radiation that is harmful to electronic devices and causes unwanted noise in measurements. Out smart shielding material minimizes the dose of ionizing radiation and eliminates the secondary radiation.
Drones and robots – in high radiation environments (e.g. nuclear disaster zones, nuclear power plants, scientific systems) devices such as cleanup and repair robots or surveillance drones are exposed mostly to high energy electromagnetic radiation, which cannot be completely shielded (weight or thickness limitations). Similarly to space applications, our material can minimize the dose of ionizing radiation, eliminate the secondary radiation and therefore increase the lifespan of the systems.
How It Works
Our smart shielding material consists of multiple layers, where each of them has a specific role;
Layer 1 is selected based on the application – either for drones or satellites. In the case of drones, the purpose of the first layer is mainly to provide protection against corrosion in moist chloride containing environments. In the case of satellites, the first layers role is to reduce the energy and intensity of secondary ionizing radiation that is created during its interaction with high velocity particles in space (e.g. protons, electrons etc).
Layer 2 is a high atomic number material (e.g. lead, gold, tungsten), that absorbs high energy electromagnetic radiation. In the case of gamma rays exceeding the energies of 2-5 MeV, the efficiency of the second layer depends on its thickness. For instance, the second layer may block almost all of x-rays but only a percentage of gamma rays.
Layer 3 consists of a number of sub-layers that convert and absorb the secondary radiation, which is created in layer 2 due to absorption of gamma rays. The complete elimination of the secondary lower energy ionizing radiation (mostly x-rays) is important as it is harmful to semiconductor based electronics and also causes noise in sensitive measurements. For that purpose, the materials included in the third layer are carefully selected and their required minimal thicknesses precisely calculated.
Figure 1. The working principle of the smart radiation shielding material, which consists of a number of layers, where each layer has a unique purpose.
Development
We have already created a few prototypes of the material and tested them with radioactive sources. Our largest sample created so far is 100 x 100 x 3 mm (Fig. 2). Selecting the materials and calculating the thicknesses was the easy part in the development. Now, we are working on the more difficult part, which is making the final product suitable for using on satellites (minimized outgassing, resistance to cyclical heating and cooling) and drones (corrosion resistance). Some of our first prototypes are also planned to be tested on the Estonian student satellite ESTCube-2 and possibly by other potential partners.
Figure 2. Smart radiation shielding prototype (100 x 100 x 3 mm), with an aluminium exterior.